The invention relates to the arrangement of a scarfing burner for removing the slag bead produced in flame cutting of a workpiece.
In flame cutting, especially when cutting thick blocks and slabs, a so-called slag bead is produced on the side of the workpiece adjacent to the cut surface--usually at the bottom--which is connected with the base material in a thin strip along the edge between the bottom and the cut surface. In normal ingot flame cutting installations, in which the continuously cast ingot is cut across into certain section lengths, the slag bead is produced at the end of the block or slab.
In the jumbo slab ingot casting installations also used in recent years, the ingot is not only cut across but the slab is divided, for example, in two narrow slabs. In this case, the slag bead is also produced along the entire length of the slab at the bottom of the above-mentioned longitudinal parallel section. Such slag beads produce irregularities and waste in the subsequent operating step, for example, rolling of a workpiece. When this relates to a slag bead which occurs in flame cutting, the roll surfaces are damaged when such a workpiece enters in the roll nip. During rolling, these slag components are rolled into the surface of the plate and consequently produce defect areas.
It is therefore necessary to remove the troublesome slag bead before processing the workpiece (block, slab or the like). This may take place, for example, by chiseling or grinding. Methods, therefore, when applied manually are often time-consuming and, therefore, not economical.
It is furthermore known to remove the slag bead by scarfing. In the equipment of German DE-PS No. 12 87 421 this is accomplished by directing the scarfing burner exclusively towards the bottom of the workpiece carrying the slag bead and, to be sure, at a certain angular setting to the workpiece. In the process according to DE-OS No. 28 31 152, the slag bead is melted and removed by means of a burner arrangement consisting of several burners whereby the burners which partly enclose the edge carrying the slag bead are directed towards the bottom and the cut surface. In both cases, therefore, the slag bead is melted in the area of the workpiece, where it is clearly visible, by one or more scarfing burners.
It was demonstrated that such an arrangement of scarfing burners is very expensive commercially. Either the workpiece must be turned or a cumbersome overhead scarfing must take place. The required number of scarfing burners is also increased since scarfing not only exclusively takes place in the cut surface area.